Problem: Solve for $x$ : $6\sqrt{x} - 4 = 8\sqrt{x} + 7$
Answer: Subtract $6\sqrt{x}$ from both sides: $(6\sqrt{x} - 4) - 6\sqrt{x} = (8\sqrt{x} + 7) - 6\sqrt{x}$ $-4 = 2\sqrt{x} + 7$ Subtract $7$ from both sides: $-4 - 7 = (2\sqrt{x} + 7) - 7$ $-11 = 2\sqrt{x}$ Divide both sides by $2$ $\frac{-11}{2} = \frac{2\sqrt{x}}{2}$ Simplify. $-\dfrac{11}{2} = \sqrt{x}$ The principal root of a number cannot be negative. So, there is no solution.